Post-ischemic inflammation at the level of brain endothelium plays an important role in pathology of ischemic stroke. The proposed approach aims to inhibit post-ischemic inflammation at the blood-brain barrier (BBB) in ischemic stroke using a novel dual functional DNA complex (GS24-NF?B). The GS24-NF?B consists of two functional units: DNA aptamer (GS24) and NF-?B decoy, which have the function of targeting transferrin receptor (TfR) for complex uptake and inhibiting NF-?B activity in the BBB respectively. The objective of this application is to effectively deliver NF-?B decoy into the bran with a goal to protect neuron from injury/death under cerebral ischemia/reperfusion. Our central hypothesis is that GS24-NF?B complexes protect neurons against cerebral ischemia/reperfusion (IR)-induced injury by inhibiting post- ischemic inflammation. This hypothesis is based on our recent preliminary data: 1. GS24-NF?B complex can be delivered into mouse brain-derived endothelial cells. 2. NF-?B activity and its downstream inflammatory cytokines, VCAM-1 and ICAM-1, are up-regulated under inflammatory condition in vitro and Oxygen Glucose Deprivation /Reoxygenation (OGD/R) condition. 3. GS24-NF?B complex inhibits activation of NF-?B, up-regulation of VCAM-1 and ICAM-1, and monocyte adhesion induced by TNF-? and OGD/R. 4. TfR-mediated transport at the BBB exists in the ischemic area of the brain under IR condition in vivo. 5. IR disrupts the BBB integrity leading to permeability o the BBB increase. We will pursue the following specific aims: Specific Aim 1: Determine pharmacological activity of GS24-NF?B in vitro. We will characterize the binding/uptake of GS24-NF?B by mouse primary brain endothelial cells in detail, and pharmacological activity of the GS24-NFkB in vitro. Specific Aim 2: Application of GS24-NF?B for treatment of ischemic stroke in vivo. Transient middle cerebral artery occlusion ischemic stroke model (MCAO) will be used as an IR model in vivo. We will access the therapeutic effect of GS24-NFkB on ischemic stroke. This proposal is highly significant and innovative, because it will explore a new research horizon and continue its innovation in brain drug delivery and therapy of ischemic stroke. The project is also of significance in strengthening the education and research environment in neuroscience and brain drug delivery in College of Pharmacy at University of Cincinnati.